Internal combustion engine



Dec. 15, 1942. HELLWEG 2,305,310

INTERNAL COMBUSTION ENGINE Filed Jan.'l 1940 'IIIIII III II Jnrenfor fl un' 4-1. fin d/ M Affomey Patented Dec. 15, 1942 pQ fI'ED STAT ES PATENT ,o FicE m rnanar. ooomus'uon'nsoms Kurt Hellweg, Frankiort-on-the-Main, Germany; vested in the Alien custodian 1 Application January InGermany My invention relates toimprovements in internal combustion engines, and more particularly in engines of the type comprising a plurality of cylinders having a common combustion chamber, and pistons reciprocating therein in opposite directions towards and away from said combustion chamherand connected by crank mechanism, one of the said pistons being. connected with a pump or compressor for supplying fluid under pressure. One oi the objects of the improvements is to provide an engine oi this type in which the forces transmitted to the crank 17, 1940, Serial No. 314,332

January 25, 1939 mechanism are comparatively small. and withthis object in view my invention consists in constructing the working pistons and the crank mechanism in sucha way that the power .transmitted from the fuel to the different pistons is difl'erent, and connecting a piston taking up higher power with the said pump or compressor for supplying fluid under pressure. I

For the purpose oi explaining the invention several examples embodying the same have been illustrated in the accompanying drawing, in

which Fig. 1 is a somewhat diagrammatical sectional elevation showing an engine comprising two aligned cylinders made integral with each other and :having their pistons connected through 14.6mm. lol ies-51) Fig. 5 is a detail view, and I Fig. 6 shows the diagrams oi two-pairs oi .cooperating working pistons and compressor pistons.

In the example shown in Fig. 1 the engine comprises a casing i cast-integral with two aligned cylinders 1 and 3 for working pistons 4 and I, and two cylinders l and 1 for pistons 8 and I, the cylinder i and its piston 8 having the function to supply air for scavenging, and

the cylinder 1 and its'piston 9 having the function to supply air under pressure. in the figure the pistons 8 and l arevcast integral with tubular extensions of the pistons 4 and 5 and the intermediate portions of the said pistons are formed with upper and lower slots or cutout portions Ill and ii. In the bottom part or the casing l crank mechanism is located which comprises a shaft l2, crank arms l3 and connecting rods l4, the said connecting rods being jointed each to an arm I! secured to a shaft 16. To the said shaits l4 upwardly directed arms i1 7 are secured which are passed through the lower rocker armsmounted upon iulcrums and cona meeting rods with a crank shaft, the working pistons or the engine being made integral respectively with the piston oi the pump or compressor supplying a fluid under pressure and with the piston oi a compressor for supplying air for scavenging.

Fig. 2 is a sectional elevation illustrating a modification, the flgure showing the working pistons, the pistons oi the pumps or compressors and the crank mechanism, the working pistons being separate from the pistons oi the pumps or compressors and connected therewith by connecting rods, I

Fig. 3 is a diagrammatical elevation similar to theone illustrated in Fig. 2 and showing a modiiication in which the working pistons and the pistons 01 the pumps or compressors are located with their axes parallel and displaced from each,

other, the piston rods being connected to the arms forming parts of the crank mechanism at points different distances. away from the inicrums of the arms,

Fig. 4 is an elevation similar to the one illustrated in Fig. 2 and showing a modification in which the said arms are yieldingly mounted and directly connected with the pistons,

slots it and II and into the tubular extensions of the pistons 4 and 5 respectively, and which are connected to connecting rods IO jointed to the pistons 4 and 5 at I. In the positions of the parts shown in the flgure the pistons 4 and 5 are nearly in their'inner dead centers, and in these positions they provide a combustion chamber 20 into which opens an injection valve 2|. The left hand cylinder I is provided with an exhaust slot or slots 22 and the right hand cylinder 2 with a scavenging slot or slots 23 connected with the cylinder Q through a passage 24 and a port 24 made in a cap 28, the supply of air from the cylinder 8 being controlled by intake valves 21 and a delivery. valve or valves 28. The cylinder 1 is provided with intake valves 28 and a delivery valve or valves 3i opening into a tubular member 30 small. while the power needed for supplying fluid under pressure is high. and accordingly the piston 0 working in the cylinder I is connected to the piston I whichdevelops higher power. This re- As shownare spaced from each other to sult may be attained in various ways. For example, the piston may have a larger stroke or a larger diameter than the piston 4. In the construction shown in the figure the result is attained by the construction of the crank mechanism, as will appear from the following: The crank shaft I2 is rotated in clockwise direction, as is indicated by the arrow x, and therefore the piston 5 has a certain lead relatively to the piston 4. As shown, the crank arms ii are at an angle of 180, and when the crank arms have been slightly rotated from the positions shown in the figure and the pistons 4 and 5 are in their inner dead centers the connecting rods I 4, [4 are symmetrical to the crank arms. Thus both pistons are simultaneously in their inner centers. But upon further rotation of the crank arms the piston 5 moves outwardly at higher speed than the piston 4. Thus, the exhaust slot or slots'22 are opened by the piston 5 before the scavenging slot or slots 23 are opened by the lagging piston 4. Thus, if the exhaust slot or slots 22 are opened sufiiciently in advance of the scavenging slot or slots 23, the distance between the median line of the engine and the beginning of the exhaust slot is a little smaller than that between the said median line and the beginning of the scavenging slot or slots 23. In a similar way the piston 5 leads relatively to the piston 4 also during the inward stroke of the said pistons, and therefore the exhaust slot or slots 22 are closed prior to the scavenging slot or slots 23, and thus the cylinder is additionally charged with scavenging air after the exhaust slot has been closed. By reason of the lead of the working piston 5 more power is transmitted to the piston 5 than to the piston 4.

Fig. 6 shows the diagrams of the working cylinders, and it shows that the power taken up by the left hand piston 5 is much larger than the power taken up by the right hand piston 4. Therefore a considerable part of the power developed by the engine is directly transmitted from the left hand piston 5 to the piston 9 of the compressor, while the piston 8 supplying air for scavenging takes up less power. Thus a comparatively smal1 proportion of the power developed by the pistons 4 and 5 is transmitted to the crank mechanism, so that the forces acting in the said crank mechanism are comparatively small.

By providing the operative parts of the engine with proper dimensions and suitably distributing the masses the result can be obtained that the fly wheel (not shown) takes up and gives 01! only little excess power. Most of the power is directly transmitted from the piston 5 to the piston S of the compressor, and therefore the mechanical efficiency of the system is high. Further, the

transverse pressure of the pistons on the cylinders, and therefore the friction of the said pistons is small.

In the modification shown in Fig. 2 the general arrangement of the pistons and the crank mechanism is the same as that described with referand 5, 8 are not made integral. but they consist of separate parts, and the said parts are connected respectively by links 35, 36 and 31, I8 jointed to the arms I! of the crank mechanism. Thus, in the operation of the engine the links 3!, ll and 31, 38 follow the arcuate paths of the Joints 8! and 40.

In the modification shown in Fig. 3 the pistons 4, 8 and 5, O are connected by links 42, 43 and 44, 45 to thearms I4 and ii at points 46, 41 and 48, 49 located respectively different distances away from the axes of the fulcrums ll. Accordingly the axes of the pistons I, O and 4, I are respectively displaced with relation to each other, and the strokes of the pistons I and I are reduced as compared to the stroke of the pistons 4 and I.

This construction is particularly suitabl in high velocity engines in which the average velocity of the pistons of the compressor and pump should not exceeds certain limit at which the velocity of the air in the valves is too high and therefore the emciency of the compressor is low. Further, in case or multi-stage compressors it is preferred to construct the pistons of the stages which have higher loads with smaller strokes. This'may be effected in a simple way by selecting the proper positions for the joints 44 and 4!. In such multistage compressors the low pressure piston will be connected to the outer end of the lever Ii, while the piston of the high pressure stage is connected to the arm Slat a point nearer the fulcrum l4. In the modification shown in Fig. 4 the construction of the working pistons 55, II and the pistons 81, 54 of the pumps orcompressors is the same as that of the pistons described with reference to Fig. 1, and the pistons 51 and ll are formed on extensions of the pistons II and II.

The arms 59, 6| are directly Jointed to the extensions of the pistons 55 and I4 at II, and, therefore, the fulcrums 42 are mounted for yielding transversely of the axis of the pistons il, 44. As shown the said fulcrums are connected with links 43 pivotally mounted at 44. Thus, when the pistons reciprocate, and the pivot bolts 4|, 4| perform rectilinear movements the fulcrums 42 are moved through transverse arcuate paths around the pivot bolt 44. As shown the length of the left hand arm ll is somewhat larger than that of the right hand arm 49, so that the stroke of the piston 56 is enlarged relatively to that of the piston 55, and the piston 44 takes up greater power than the piston 55.

Preferably, the pivot bolt 44 is eccentrically mounted, as is indicated in Fig. 5. Thus, by turning the eccentric disk 45 the distance between the pistons 55 and 58 and thereby the capacity of the combustionn chamber may be varied. Of course, suitable means are provided for fixing the eccentrics 65 in set positions. As shown such means consist of a disk 66 keyed to the pivot bolt 84 and a screw 41 passed through a slot 48 made in the disk 64 and screwed into the eccentric disk 45.

In my improved engine the masses may be balanced by proper dimensions of the individual parts, and by properly positioning the Joints of the mechanism. Where the stroke of the piston 4 (Fig. l) is smaller than that of the piston I the masses may be balanced by varying the masses of the pistons accordingly.

In describing the invention reference has been made to an engine which comprises two working pistons. But 'I wish it to be understood that my invention is not limited to this construction, and that more than two pistons may be mounted in cylinders having the combustion chamber in .1 a plurality of sets of t :4 ed axially one beside the other ion have the crank shaft H2 in common.

1 c 3i: i

i. an internal combustion engine, comprising cylinders a combustion chamber in com-- mon, wort pistons located therein, crank mechanism connecting said pistons so as to cause the same to move in opposite directions, said pis-x tons and. crank mechanism being constructed-so piston supplying fluicl under pressure.

An internai'ccmbustion engine as claimed in claim 1, in which the working piston taking up more power is made integral with said pump piston supplying fluid under pressure.

crank mechanism connecting the said piston with the crank shaft.

5. An internal combustion engine, comprising a combustion chamber in comother one, pumps and pump pistons one for suppiyin I fluid under pressure and the other one for air for scavenging, said pump piston fluid under pressure being con- ;h one of the parts consisting of said piston taking up more power than the We of the said crank mechanism connecting the saiei piston with the crank shaft,

6. An internal combustion engine as claimed in claim 5, in which the crank mechanism is coni, An internal combustion in which the said working pistons have difierent 8. An internal combustion claim 1, in which 9. An internal combustion engine as claimed in claim 1, in which 

